Surface-mounted chip-type electronic parts such as ICs as well as transistor, diodes, capacitors and piezo-electric element registers are supplied in the form packaged in a carrier tape package comprising a plastic carrier tape (hereinafter simply referred to as a “carrier tape”) having continuously emboss-formed pockets capable of housing the parts in response to shapes of the parts and a carrier tape lid (hereinafter sometimes simply referred to as a “lid”) heat-sealed to the carrier tape. The electronic parts therein contained are automatically taken out from the carrier tape after peeling off the lid of the carrier tape package, and surface-mounted on an electronic circuit board.
Along with the recent remarkable improvements achieved in the surface-mounting technology, these electronic parts transported or otherwise handled in the above-mentioned carrier tape package have improved performance and are downsized. These electronic parts may be broken under the effect of electrostatic discharge as a result of contact between the carrier tape emboss inner surface or the lid inner surface and the electronic parts caused by vibration during transportation of the carrier tape package. A similar trouble may occur from static electricity produced upon peeling off the lid from the carrier tape. Measures against electrostatic troubles have therefore been the most important problem to be solved in the carrier tape and the lid.
A charge preventing treatment (an antistatic treatment) of a carrier tape has conventionally been accomplished through kneading of carbon black into a material used, or coating, giving satisfactory effects. For the lid, however, transparency to an extent permitting visual recognition of the contents is required. Since an antistatic treatment similar to that for the carrier tape cannot be conducted, therefore, the following antistatic treatments have been proposed:
(1) Kneading a surfactant-based antistatic agent into plastics, or conducting coating onto a plastic surface;
(2) Laminating aluminum foil films;
(3) Coating a plastic resin prepared by kneading a metal oxide-based conductivity agent such as tin oxide.
The method (1) above has, however, a problem in that the antistatic function deteriorates or even disappears under a low-humidity condition. The methods (2) and (3) above have a problem in that transparency of the lid cannot be maintained, and visual recognition of the contents is difficult or even impossible.